Concurrent administration of chemo-endocrine therapy for postmenopausal breast cancer patients

Concurrent chemo-endocrine treatment for early hormone-positive breast cancer: a no-go???

PURPOSE

Endocrine therapy is one of the cornerstones of early breast cancer treatment. While this medication could be initiated on the day of diagnosis, it is often postponed until after completion of surgery, radiotherapy, and chemotherapy. This practice is based on preclinical data suggesting an antagonistic effect between endocrine therapy and cytostatic agents, and on the interpretation of clinical trials comparing concurrent versus sequential use of tamoxifen and chemotherapy. These clinical trials, however, have never shown a statistically significant difference in overall survival or disease-free survival and focused on tamoxifen rather than aromatase inhibitors. Nevertheless, sequentially administered endocrine and chemotherapy have become standard of care worldwide.

RESULTS

We performed a literature review and conclude that concurrent endocrine chemotherapy is at least as effective as sequential treatment. In fact, higher response rates have been observed in trials with aromatase inhibitors rather than tamoxifen in a neoadjuvant setting.

CONCLUSION

We encourage breast cancer oncologists to re-consider concurrent endocrine chemotherapy as a possible treatment strategy enabling early start of potentially curative endocrine treatment.

Development, Characterization and In Vitro Evaluation of Paclitaxel and Anastrozole Co-Loaded Liposome

Paclitaxel (PTX) and anastrozole (ANA) have been frequently applied in breast cancer treatment. PTX is well-known for its anti-proliferative effect meanwhile ANA has just been discovered to act as an estrogen receptor α (ERα) ligand. The combination therapy of PTX and ANA is expected to improve treating efficiency, as ANA would act as a ligand binding with the ERα gene expressed in breast cancer cells and thereafter PTX would inhibit the division and cause death to those cancer cells. In this study, liposome-based nanocarriers (LP) were developed for co-encapsulation of PTX and ANA to improve the efficacy of the combined drugs in an Estrogen receptor-responsive breast cancer study. PTX-ANA co-loaded LP was prepared using thin lipid film hydration method and was characterized for morphology, size, zeta potential, drug encapsulation and in vitro drug release. In addition, cell proliferation (WST assay) and IN Cell Analyzer were used for in vitro cytotoxicity studies on a human breast cancer cell line (MCF-7). Results showed that the prepared LP and PTX-ANA-LP had spherical vesicles, with a mean particle size of 170.1 ± 13.5 nm and 189.0 ± 22.1 nm, respectively. Controlled and sustained releases were achieved at 72 h for both of the loaded drugs. The in vitro cytotoxicity study found that the combined drugs showed higher toxicity than each single drug separately. These results suggested a new approach to breast cancer treatment, consisting of the combination therapy of PTX and ANA in liposomes based on ER response.

Concurrent or Sequential Hormonal and Radiation Therapy in Breast Cancer: A Literature Review

Background and objectives: Adjuvant hormonal therapy is frequently used in the treatment of women with estrogen receptor (ER)/progesterone receptor (PR) positive breast cancer. When radiotherapy is given, hormone therapy may be delivered in a concurrent or sequential manner. Hormonal blockade with tamoxifen or aromatase inhibitors is thought to arrest hormonally dependent cancer cells in the early G1 phase of the cell cycle. This has been theorized to reduce the efficacy of radiation, which is known to be more effective in cells that are actively dividing. Therefore, there has been a reluctance by many to treat with concurrent hormonal and radiation therapy.

Methods: We performed a search of the Medline database that led to the identification of 39 studies. Abstract and full-text review of these studies led to the identification of seven English non-review studies in peer-reviewed literature between 1995 and 2015 that addressed the question of timing of radiation and hormonal therapy. Outcome measures were captured from each of the studies.

Results: No difference in survival or local-regional recurrence was identified between concurrent versus sequential treatment. Furthermore, no difference in cosmetic outcome or adverse effects was noted for either approach. However, when comparing radiation alone or radiation and hormonal therapy, there was an increased risk of breast and lung fibrosis with combined treatment.

Conclusions: Hormone therapy, concurrent or sequential, with radiation results in comparable disease-related outcomes, including survival and recurrence. However, given the theoretical reduction in efficacy and increased rates of fibrosis with concurrent use, it is reasonable to support the use of sequential therapy.

The efficacy and safety of neoadjuvant chemotherapy +/- letrozole in postmenopausal women with locally advanced breast cancer: a randomized phase III clinical trial

This two-arm randomized clinical study aimed to evaluate the efficacy and safety of neoadjuvant concurrent chemotherapy and letrozole in postmenopausal women with locally advanced breast carcinoma. One hundred and one postmenopausal women aged 50-83 years with pathologically proven locally advanced (clinical stage T3, T4 and/or N2, N3) breast cancer were randomly assigned to receive neoadjuvant chemotherapy alone (control arm, n = 51) or neoadjuvant chemotherapy concurrent with letrozole 2.5 mg (study arm, n = 50). Chemotherapy consisted of a median 4 (range 3-5) cycles of intravenous 5-fluorouracil 600 mg/m(2), doxorubicin 60 mg/m(2), and cyclophosphamide 600 mg/m(2), every three weeks. All patients subsequently underwent modified radical mastectomy approximately two weeks after the last cycle of chemotherapy. Pathologic complete response rates were 25.5% and 10.2% in the study and the control group, respectively (P = 0.049). Similarly, clinical complete response rates were 27.6% and 10.2% in the study and the control group, respectively (P = 0.037). In the subgroup analysis of hormone receptor-positive cases, the complete response rates were more prominent in study group compared with control group. Common treatment-related side effects such as nausea, vomiting, bone marrow suppression, and mucositis were similar in both groups, but hot flush was more prevalent in study group compared with control group (P = 0.023). The addition of letrozole concurrently with neoadjuvant chemotherapy provides a higher clinical and pathologic response rates with acceptable toxicity compared with chemotherapy alone in postmenopausal women with locally advanced sensitive breast cancer.

Concurrent vs sequential adjuvant chemotherapy and hormone therapy in breast cancer: a multicenter randomized phase III trial

BACKGROUND

The most appropriate timing of chemotherapy and hormone therapy administration is a critical issue in early breast cancer patients. The purpose of our study was to compare the efficacy of concurrent vs sequential administration of adjuvant chemotherapy and tamoxifen.

METHODS

Women with node-positive primary breast cancer were randomly assigned to receive tamoxifen (20 mg/d for 5 years) during (concurrent arm) or after (sequential arm) adjuvant chemotherapy. Chemotherapy consisted of alternating regimens of cyclophosphamide, epidoxorubicin, and 5-fluorouracil and cyclophosphamide, methotrexate, and 5-fluorouracil every 21 days for a total of 12 cycles. The primary endpoint was overall survival (OS), and secondary endpoints were toxic effects and disease-free survival (DFS). No provision for interim analyses was made in the original study protocol. Survival curves were estimated by the Kaplan-Meier method. Multivariable Cox regression models, adjusted for age, menopausal status, tumor stage, and lymph node and hormone receptor status, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

From 1985 to 1992, 431 patients were randomly assigned and studied according to the intention-to-treat principle. After a maximum of 15.4 years of follow-up (median 12.3 years), the estimated actuarial 10-year OS was equivalent for the two study arms (concurrent arm: 111 patients, 66%, 95% CI = 59% to 72%; sequential arm: 114 patients, 65%, 95% CI = 59% to 72%, P = .86). No differences in DFS and toxic effects were evident. Four interim analyses were performed, but no alpha error adjustment was necessary because of the largely negative results of this final analysis (sequential vs concurrent arm: HR of death = 1.06, 95% CI = 0.78 to 1.44, P = .76; HR of relapse = 1.16, 95% CI = 0.88 to 1.52, P = .36).

CONCLUSIONS

No statistically significant differences in OS, DFS, and toxic effects between concurrent and sequential adjuvant chemo- and hormone therapies were observed. Our study does not support the superiority of one schedule of chemo- and hormone-therapy administration over the other. However, because of the limited statistical power of the study, these results must be considered with caution.